Support per-layout translations entries

[romanz]

Following #4489.

Also, use layout names for translation font keys.

[github-actions]

core UI changes	device test	click test	persistence test
T2T1 Model T	test(screens) main(screens)	test(screens) main(screens)	test(screens) main(screens)
T3B1 Safe 3	test(screens) main(screens)	test(screens) main(screens)	test(screens) main(screens)
T3T1 Safe 5	test(screens) main(screens)	test(screens) main(screens)	test(screens) main(screens)
All	main(screens)

[romanz]

I will reorganize the commits above, in order to separate the text-modifying edits into a separate commit (which can be dropped - to avoid UI changes).

[romanz]

i.e., there is no diff between 8952a98 and 4148e87, just reorged the commits' content by the above force-push.